This program is very similar to "e02_Switch_input01" in principle, except that it sends a more specific human-readable messages to the serial monitor instead of "1"s and "0"s.
Again, this program outputs only to Serial Monitor of Arduino. There is no other output (i.e. LEDs are not used).
To open Serial Monitor, you need to click the magnifying glass icon at the top-right of Arduino application.
(Serial Monitor Button)
A "if...then...else" statement (or conditional statement) determines which message is to be sent (which line of codes to be executed) depending on the state of two switches (see if... in Arduino's reference page). For example, if both switches are pressed ("0" and "0"), Arduino sends "both ON" to the serial monitor. Please note that Arduino ports receive "0" when a switch is pressed. (see Activ-high and Active-low)
